Lipid metabolism Flashcards
How are lipids broken down?
Broken in to micelles in small intestine, absorbed as chylomicrons
Name chylomicron packages
VLDL, LDL, IDL, HDL
How do chylomicrons get in to adipocytes?
Insulin binds to receptors and activates GLUT4 which allows chylomicrons, glucose and short chain fatty acids across membrane
Where does synthesis of TAG occur?
Cytoplasm only
What is committed step of FA synthesis?
Acetyl CoA Acetyl CoA carboxylase to Malonyl CoA -> fatty acid chain
What stimulates Acetyl CoA Carboxylase?
Citrate, INsulin
Ibhibited by AMP, Glucagon, Epi
Where are fatty acids activated to be targeted by B-oxidation?
Cytosol
Where does B-oxidation occur?
Inner mitochondrial matrix
When does B-oxidation run at a high rate?
When glucose is low
Name the fatty acid chains released from TAG to get glycerol backbone
TAG -> Dag -> Mag
How many carbons are cleaved at a time during B-oxidation?
2 carbons at a time to release an Acetyl CoA
How do fatty acids get in to mitochondria?
Faty acid activated to Fatty Acyl-SCoA
Fatty acyl SCoA uses Carnitine Transferase -> Fatty Acid Carnitine (inner membrane)CoA -> Fatty Acyl CoA (in Mitochondrial matrix)
How many Acetyl CoAs come from a 16 carbon fatty acid?
8
What does fat burns in the flame of carbs mean?
To use acetyl CoA as energy must have glucose
One round of B-oxidation forms what 3 molecules?
1 Acetyl CoA, 1 FADH2, 1 NADH
1 Acetyl CoA from fatty acid will produce what from TCA
3 NADH (no step 0), 1 FADH, 1 GTP
How many NADH and FADH2 are produce from 1 cut of fatty acid?
1 FADH, 1 NADH
How many ATP will a 16 chain FA produce?
106
How many extra ATP is needed for a double bond?
2
16:0 = 106, 16:1 = 104
When are ketone bodies produced?
When there is no glucose for B-oxidation
Where are ketone bodies produced?
Mitochondria
What are ketone bodies?
3 water soluble compounds that are by-products from fatty acid being broken down in liver
AcetoActetate, Acetone, Beta-hydroxybutyrate
Can ketone bodies be used by the heart and brain as an energy source?
Yes, the brain uses Acetoacetate during starvation
Heart can use
What is the control of ketogenesis?
Increased level of circulating FFAs from lipolysis of TG in adipose tissue will lead to the formation of ketone bodies
